> > NVIS has shown up in several posts. I'm a big fan of acronyms but
> > I can't figure this one out. What is it?
> >
> > Ken AB5A
> >
NEAR VERTICAL INCIDENT SKYWAVE
As the excellent article on p39 of Jan 1995 QST reports, NVIS propagation
is
basically straight up radiation without any skip regions i.e. continuos
coverage out to about 400 miles.
I just modeled an 80m wire dipole over perfect ground. The EZNEC
elevation pattern showed virtually no difference in gain at all elevation
angles for
heights of 16,24, and 33 feet. The gain for height of 63 feet was down a db
or so from elevation angle of 90 deg(straight up) to 60 deg where the gain
converged with the lower heights.
PS Another helpful article in QST "Why an Antenna Radiates" , Nov 1992 p59
k7puc
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